Fluid shock absorber



Sept. 6, l1932. 1 ECKHARD 1,875,860'

FLUID SHOCK ABsoRBER Filed Aug. 29, 1930 2 Sheets-Sheet l Sept. 6, 1932. J. ECKHARD 1,875,860

FLUID SHOCK ABsoRBER Filed Aug. 29. 1930 2 sheets-sheet .2

gwomtoo J'o im Eck/mrd @WWW Patented Sept. 6, 1932 iUNI'rEn STATES 'JOHN ECKHARILOF GLNCINNATLOHIO,

FLUID sHocKABsonBnn Application filed Augl'ust 29, 1930. Seria1--N'.`478,647.

This invention relates to improvements in a fluid shock absorber such as may be employed on various types of vehicles.

An object of the invention` is to provide an improved Huid shock absorber wherein is eliminated the lost motion due to frothing or foaming ofthe iiuid when the device is in operation.

Another object is to provide a iuid shock absorber with means for precluding the formation ofV a vacuum and of air pockets in the piston chamber thereof when the piston is actuated, thereby precluding also foaming or frothing of the fiuid, which conditions would result in rendering the device vacuum bound, air bound or foam bound..` f

Another object is to providel a shock absorber with means for the above purpose, which is simple and inexpensive toA manufacture.

Another object is to prov-ide means in a shock absorber whereby the piston chamber thereof is automatically replenished with fluid from a normally non-communicating reservoir, by the action of the piston.

Another object is to provide an improved arrangement of safety valves'for precluding bursting of the device when subjected to eX- cessive shock. A

Another object is to provide a readily adjustable means whereby movement of' the piston in two directions may be independent-ly controlled and whereby the `device may instantly be adapted for use on opposite sides of a vehicle,`without disassembly.

These and other objects are attained by thel means described herein and disclosed in the accompanying drawings, in which:

Fig. 1 is a front elevational vievvgof` the device of the invention.

Fig. 2 is a rear elevational view ofthe def vice shown in Fig. 1.

Fig. 3 is a side view of the device of the invention. j

Fig. 4 is a cross-sectional view taken on line 4-4 `of Fig. 3.

Fig. 5 is an enlarged elevation-al view of the shock absorber` piston.

Fig.` 6 is a .cross-sectional view taken on line 6-,6of Fig. 3.

, Fig. 7 Ais a rear lelevational View of a dividfingiplate shown in frontelevation in Fig, 4.

F ig. Sis a side view of the dividing plate taken Online 8,-8. of F ig,l 7. Y 4 j Fig. 9y is a cross-sectional view taken through the piston vshaft bearing of thel shock absorber.

One oftheimportant objects of the present invention is to render a shock absorber. of the herein disclosed type smoother in operation by.` eliminating` the formation of froth or air bubbles which,L inv the ordinary fluid shock absorber, result from the violent in'- termiXing of the shockv absorber fluid and air which finds Aits way into the piston chamber duringoperationof the device.. The presenceV of readily compressible` air or froth in the piston chamber of a shock absorber ldesigned for fluid-operation only, permits comparatively unret'arded movement of the piston during a portion ,of its stroke, Wherefore, this portion of the stroke` cannot be of usel in absorbing shock-.transmitted to the piston by thearm 12, whichisoperatively connected with either: the spring or the axle of ya vehicle, as is well known.V Theshoclr'absorber becomes airbound or foam bound when air is presentl for the piston to work-on, and vacuum boundwhenthere is insufficient fluid on oneside of the-piston. These conditions are eliminated by providingthe means about to be'fdescribed. Y Y The shock absorber .casing comprises the base plate 13. which is provided with means suchasrperforations 14 whereby the base plate may be .secured to the frame or other stationary part of a. vehicle.. The base plate has Perfectly flat interior surface 14 provided with a series of perforations 15" arranged in a circle. for the reception of bolts 16;which` secure the cylindrical piston housing member` '17 upon the base plate. Said` housingv member is pro-vided with a depression .or ,cylinder 18, .forming ka piston. chamber, having acurved inner wall 19 for; cooperation withthe piston 20,

The end of the piston has sliding contact upon the curved' wall A1.9 of the piston chamber.` At 21' is indicated a-machined flange in` which are formed! threaded .perforations Y the piston housing member upon the flatface of the base plate 13. Y

The housing member 17 is divided, by means of a dividing wall plate 23, to provide the piston ,chamber 18 yand a fluid reservoir 24. Thecontinuous' dividing wall25, which extends kfrom the flat innery wall 2tV of the piston housing member to the flat faceV 14 of the base plate, has a mid portion 27 which provides a bearing forth'e' hub 28 of the piston.

extension 30 of said shaft is received in a depression or bearing 31 ofthe base plate. From'the foregoingit yshould be apparent that bv actuating'the arm 12, the piston may be moved within' the piston `chamber to lan' extent limitedI by the dividing wall of the plate 23. The dividing wall of plate 23 is precluded from .relative movement within the housing member 17, by a dowel pin 32 extending inwardly from the face 26'and received in a perforation 33 of the` dividing plate. The plate may 'be'furt-her precluded from relative movement byproviding a bolt 34 passing through and engaging a threaded bore 35 in the material of the housing member, At V361is represented a filler opening plug which may beremoved for replenishin'g the supply voffluid in the reservoir of the piston chamber. l v Y g -In the absencel ofiair in the piston cham- Y ber, the shock absorber fluid isforc-ed from one side of the'piston to the other,-through a pair "of constricted fluid passages* 37 and 38 each of which is provided "with a oneway check valve and a needle valve for limiting flow of fluid through the check valve and its cooperative passage. The bores of the'passages extend Vin parallelism diametrically of the'base plate, and they are so located with respect to the dividing plate wall that each may vcommunicate with the piston chamber onfthe oppositel sides' y'of the piston. Passage 37 communicates with the piston chamber by means of a fluid passage inlet 39 and a fluid passage outlet 40'disposed on opposite sides of the piston. Fluid passage 38 has a communicating fluid passage'inlet 41 anda fluid paslsage outlet 42 communicating with the piston chamber on opposite sides of the piston. It should be noted that the fluid passage outlet of one fluid passage communicates with the piston chamber at the same side of the piston with which the fluid passage inletof the second fluid passage is inI communication. It should be clear from the disclosure in Fig. 2, therefore, that upon movement-of the piston plate 20 toward the right, fluid `will be forced i lthrough the outlet 40 and passage 37 to be side ofthe piston.

discharged from the inlet-39 to the opposite rlvhis displacement i of fluid through the opening 41 is precluded by The piston shaft 29 extends` Vthrough a piston shaft bearing 300 located centrally of the housing member `17 and an Yseat at 47'and 48, respectively. Y In each of the 'passages 37 and 38, a needle valve seat and a ball check valve are located between the inlet and outlet ports.

It is of importance that the size of the passages 37 and 38 be no larger than is necessary to convey the maximumV amount of fluid passing' therethrough lunderl ordinary conditions.

By having l,these passages small Vor constricted, there is effected a greatreduction' in the agitating of theifluid'during operation of the device. Itshould be noted that thesepassages provide the only means whereby Huid may pass from one side of the piston 4to 'the e -fluid from thepiston chamber into the reservoir. .The depressions 54 and 53 in the rear` and front faces, respectively, of the ydividing wall plate, communicate with the piston chamber and reservoir, respectively.v From the foregoing it shouldbe apparent that fluid leaking from the piston chamber along the piston shaft, will be replaced by fluid suckingk from the reservoir through the valves 49 and 50. Means are providedffor returning to the reservoir, that fluid which is forced outwardly towardthe packing nut 55 by reason of the high pressure developed within the piston chamber. Said means comprises an annular groove 56' formedv in the bearing 30, which groove communicates, bymeans of ay passage 57, with an opening 58 formed in the portion of the dividing wall plate that forms part of the reservoir. The fluid that is returned to the reservoir through these passages, is sucked intol the piston chamber, through the valves 49 and v50, by the action ofthe piston. 'It' is to be understood that at 49 and 50-Aare .ball

other means of returning theleakage to the p Y at 60. 'Meansfor precluding bursting of the v device when subjected to Vsevere shock, is loing and an 'inlet opening and that by overcoming the resistance offered by the spring urged check valves, 'fluid may pass through the piston vfrom one side ofthe piston chamber to the other. The valves are so arranged that they Will remain closed under ordinary conditions, but may be opened in the event that the piston is subjected to severe or extreme movement in either direction of pistonmovement. These valves, therefore, are normally inoperative.

When in use, the needle valves 45 and 4:6 ordinarily are adjusted to permit different amounts offluid passage whereby to effec- 'tively absorb shock due to both the compression and rebound of `a vehicle spring. In order to make use of a shock absorber previously installed on one side of a vehicle, `it yusually is necessary to change the adjustment of the needle valves so that the amount of iuid thathad .passed through passage 37, for example, Will pass through passage 38, and thatfthe amount that previously had passed through .passage 38 will pass through passage 37. This change in adjustment requires no removal or replacement of parts, it being necessary merely to applya tool to the heads of the needle valves and adjust them `to provide the proper size of opening. VIt is to be understood that various modifications and changes in structural details of the device may bevmade Within the scope of the appended claims, Without departing from the spirit of the'invention. Y

V`What is claimed is: Y '1. Ina device of the class `described the combination of a movable piston and a di,- videdhousing therefor providing a reservoir and a piston chamber in which the piston may movefthe piston serving to divide the piston chamber, a pair of'iiuid replenishing valves each normally yieldingly seated and adapted for communicating with the 4reservoir, one ofthe valves being in communication With the piston chamber at one side of the'piston and the other being in communication With the piston` chamber atthe other side of the piston, said valves being arranged to preclude passage offluid fromthe pist-on chamber to the reservoir but to yield and open by suctionof the piston to permitl passage of small amounts of fluid from the reseryoir to the piston chamber to compensate for fluid leakage from the piston chamber, and independent passage means each norn mally-serving to convey Vfluid from one side 65 of the pistonfto-the otherupon movement f justment.

of the vpiston Vthe passages each' including a 2. Ina device of Ithe class described v'the combination of, a movable piston and a 4d-i- 70 vided housing therefor "providing a nreservoir and a piston chamber in which the piston may move, the piston serving to divide the pistonf chamber, a pair of fluid replenishing valves each normally yieldingly seated and 75 adapted for communicating Withvthe :reservoir, one Vof the valves being in communication With the piston chamber at one side of the piston and the other being in communi cation with the piston chamber at Vthe'othermg@ side of the piston, said valves being arranged to preclude passage ofiluid Yfrom the piston chamber to thereservoir but to yield and open by suction of the piston to permit passag'eof small amounts of fluid from the reservoir tonga;

`the piston chamber, a ffiXed valve controlled one-Way passage .means forthe conveyance of fluid from vone side of the vpiston tothe other, and a ysecond fixed valve controlled one-Way passage means entirely independentioo of the first one Way Vpassage means for conveying fluid, in the opposite direction, from one side of the piston Lto the other;l c i ln a device of the class vdescribed the combination o'f-a movable piston-and a ldi-iee vided housing therefor providing a reservoir and a piston chamber in Which'the piston lmay move, the piston serving -to divide the piston chamber, a pair of fluid replenishing Vvalves each communicating with the -reser-Lfloc voir, one of the valves being in communication Withthe piston chamber at one sideoffthe piston and the other being in communication With the piston chamber at the other side of `the piston, said valves being arranged toiof,

preclude passage .of fluid :from -the`lp`istonY chamberfto the reservoir but-to permit ypassage thereof from the reservoirfto the piston chamber in small amounts equal to normal leakage from the device, a one-Waypassagelsno means, including a check valve for the conveyance of fluid from'one side ofthe pistou to the other, a secondone-Way passage means Y entirely independent ofthe first one Way passage means and including a check valve forlils conveying fluid, in the opposite direction,y from one side of the piston to the other,v and ya regulatingo'valve in each passage meansv en'wah 'the-pistn Chamber ai @ne Siae' of the piston and the other being in Ycommunication With the piston chamber at the other side of the piston, said valves being arranged to sage of small amounts fof fluid from-the resi preclude passage-offfluidfrom the piston chamber to the reservoirlbut to yield and open by suction of the piston topermit paservoirto the piston chamber, acne-Way passage means forthe conveyance of fluid from onerside of thepistonto theother,'a second one-Way'passage means entirely independent l of the lirst one Way passage means for convey'ing fluid, in the opposite direction, from one side of the piston Vto the other, a valve in each passage means capable ofA fixed ad-` justment for controlling the rate of fluid pas- V`sage therethrough, a check valve in each of said passage means, andnormally inoperative means for relieving excessive pressure'that may be'built'up on either side of the piston.

5.y In a device of the class described the combination of a movablevpistonhaving a shaft anda divided housing for the piston providing'a reservoir and a piston chamber in Which the piston may move, the piston wserving to divide the piston chamber, a bearing in the housing, a pair of fluid replenishing valves each normally yieldingly seated and adapted for communicating With the res- 5 ervoir, one ofthe valves being in conf'imunica-V tion with the piston chamber at one side of the pis-ton and the other being in communica- V tion With the. piston chamber at theother side of therpiston, said valves being arranged to preclude Vpassage of fluid from the piston chamber'to the reservoir but to yield and open by 'suction of the vpiston to permit pas-y sage thereof from he reservoir to the piston chamber to compensate for fluid leakage from the piston chamber, a fluid return groove in the bearing and communicating with the reservoir for returning leakage about the piston shaft, passage means capable of lined adjustment as to capacity and normally serving to convey fluid from one side of the piston to the other upon movement 'of the piston, and a checlr valve in each of said passage means precluding fluid iloW in one direction.

6. In a device Vof the class described theV combination of a movable piston having a ishaft and a divided housing for the pistonV providing a reservoir and a piston chamber ing in the housing, a pair of normally yield- 1 ingly seated valves each communicating with the reservoir, one of the valves being in communication With the' piston chamber at one side of the piston and the other beingincommunication with the piston chamber at the:

' other side of the piston, said valves being ara ranged to `preclude passage of fluid from t1 piston chamber to the reservoir but to perinterior of the housing, said passage means;A

in which the piston may move, the piston` serving to divide the piston chamber, a bear-A the reservoir, oneof the valves being in com-- mit passage thereof from the reservoir to' the-piston chamber,afluid -return groove in the bearing and communicating with thereservoir for returning leakage about the piston shaft, a one-Way passage means for the con-e; veyance of iiuid frornone side of the piston to the other, and a second one-Way passage means entirely independent of thefirst onevvay passage means, for conveying fluid, in the opposite direction, from 'one side ofthe@V piston to the other, and a ball check valvein :each of said p ssage meansV flou7 in' one'dzrection. l *j 7. i-i base plate for shoclr absorbers comprising means' forl A attachmentto a vsupport-0 ing surface, said base plate havin@ aflat face, and a pair of substantially paraliel bores eX- tending diametrally of theV base plate, each of said bores being provided With an inlet and an outlet port, a needle val* i" precluding fluid or varying thecs capacity of the bore, anda fluid check nieans preclnding fluid flew in; one directiononly. f 8. ln a device of the class described the combination of amovablepiston and a divided housing therefor providing areservoir anggo a lpiston chamber in which the piston vmay move, the piston Vserving to divide thevpiston chamber, a base plate and means'for attachment thereof to the housing, a pairof fluid replenishing valves each normallyr yieldinglypg5V -seatedand adapted for communicating with each normally serving to convey-fluid fromY one side of the piston to the other upon move'- ment ofthe pistoni, the passages each including a check valve and a valve forlixed adjustment.y y I' 9. In a device of 'the class described the combination of a movable piston and a divided housing therefor providing a reservoir and a piston chamber in which the piston may move, the piston serving todivide the pistonV chamber, a base plate and vmeans for attachment thereof to the housing, a pair offluid replenishing valves each normally yieldingly seated and adapted for communicating Vwith munication With-the piston chamber at one side of the piston 'and the other being in comy municat-ion with'. the ypiston chamber at the other side of the piston, said valves being arranged to preclude passage o'fffluid fromtheVL 130 other, the passages each including a Check Y valve and a Valve for Xed adjustment.

In testimony whereof, I have hereunto sub scribed my name this 26th day of August;

JOHN ECKHARD. 

